the coolant temp gauge drops when idling but comes up when you step into it .changed both t-stats .pressured system no leaks found .at idle with cap off level in hose rises,but when turn on fan level drops .why is this???
You are on the right track with cap off and at idle coolent level in over flow tank will start to fill up which is normal when the thermostat starts to open level in tank will drop when this happens add anti freeze to full mark then put cap back on. That should do it.
and also blead all the air out of the system after it heats up...It is possible to get an air pocket trapped. While the engine is cold, running, WITH the heater knob on full heat and the radiator cap on, squeeze the upper radiator hose several times hard and rapidly. Then while the motor is still fairly cool, remove the radiator cap and squeeze the hose several times again, but not as hard because you'll push it out the top. Put the cap back on, let the motor heat up and squeeze the hose again several times hard again.YOU CAN ALSO DRILL THE THERMOSTATE AS SHOWN..
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